Transparent glass-ceramics with low thermal expansion coefficient, which contain a solid β-quartz solution as main crystalline phase, have been described in numerous publications, in particular by W. Hoeland and G. Beall in Glass-Ceramic Technology, Am. Ceram. Soc., Westville (2002), pages 88-96. Said glass-ceramics are generally obtained from a precursor glass (more conventionally a mixture of the constituents of said glass) whose composition is of Li2O—Al2O3—SiO2 type (LAS). Said composition may contain several secondary constituents, such as:                TiO2 and ZrO2, as nucleating agents;        alkaline-earth oxides and phosphates or fluorides to optimise fusion and microstructure in particular;        cocktails of oxides of polyvalent ions responsible for colour such as:                    [Co3O4—NiO—Fe2O3] (U.S. Pat. No. 5,179,045) for a burgundy colour,            [Fe2O3—CoO—Cr2O3—(MnO2, V2O5)] (U.S. Pat. No. 4,526,872) for a light brown colour,            [CO3O4—Fe2O3] (U.S. Pat. No. 5,422,318) for an amber champagne colour,            [V2O5—(As2O3, Sb2O3)] (U.S. Pat. No. 5,070,045) for a black to dark reddish brown colour,            [CoO—Cr2O3—MoO3—NiO)] (U.S. Pat. No. 5,010,041) for a grey to bronze colour; and            many others for specific colours as desired in given context; and                        at least one fining agent, generally As2O3 and/or Sb2O3, to eliminate gaseous inclusions from the molten glass mass.        
Said glass-ceramics are obtained by heat treating the precursor glass or mixture of constituents of said glass (the term mineral filler can be used, mineral filler itself precursor of said glass). The manufacture of articles in β-quartz glass ceramic conventionally comprises the three main successive steps recalled below:                a first fusion step to melt a mineral glass or a filler, precursor of such a glass, generally conducted at between 1550 and 1700° C.,        a second cooling and forming step of the molten glass obtained, and        a third crystallization or ceramming step of the cooled, formed glass carrying out a suitable heat treatment.        
Said glass-ceramics find application in numerous areas and in particular as glass substrate for fireplaces, cook-tops, protective lenses, security glass.
It would be interesting to develop a β-quartz glass-ceramic material exhibiting a blue coloration.